<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Microsoft-官方网站</title>
<link rel="stylesheet" type="text/css" href="font-awesome-4.6.3/font-awesome-4.6.3/css/font-awesome.css">
<!-- <link rel="stylesheet" type="text/css" href="style.css"> -->
<style>
*{
padding: 0;
margin: 0;
text-decoration: none;
list-style: none;
}
body{
font-size: 15px;
font-family: "Helvetica Neue",Helvetica,Arial,sans-serif;
min-width: 320px;
color: #000;
background-color: #fff;
}
a{
display: block;
color: #000;
}
/*header*/
header{
width: 100%;
border-bottom: 1px solid #e6e6e6;
}
header .container{
width: 90%;
height: 48px;
margin: 0 auto;
display: flex;
flex-direction: row;
justify-content: space-between;
align-items: center;
}
/*header左边导航nav部分*/
header .nav{
display: flex;
flex-direction: row;
align-items: center;
}
/*导航Logo大小*/
header .logo img{
max-height: 23px;
}
/*导航列表部分*/
header .nav>ul{
margin-left: 18px;
display: flex;
flex-direction: row;
align-items: center;
}
header .nav-content{
padding: 0 1.5em;
line-height: 48px;
position: relative;
}
header .nav-content:hover{
background-color: #f2f2f2;
}
/*二级导航*/
header .nav2{
position: absolute;
top: 0;
left: 0;
}
</style>
</head>
<body>
<header>
<div class="container">
<nav class="nav">
<a class="logo" href="#">
<img src="imgs/microsoft.png">
</a>
<ul>
<li>
<a class="nav-content" href="#">
商店
<i class="fa fa-angle-down"></i>
<ul class="nav2">
<li>
<a href="#">微软官方商城</a>
</li>
<li>
<a href="#">寻找店铺</a>
</li>
</ul>
</a>
</li>
<li>
<a class="nav-content" href="#">
产品
<i class="fa fa-angle-down"></i>
</a>
</li>
<li>
<a class="nav-content" href="#">
支持
</a>
</li>
</ul>
</nav>
<!-- <div class="header-right">
<div class="search">
<input type="input" name="search" placeholder="在Microsoft.com中搜索">
<button class="fa fa-search" type="button"></button>
</div>
<a href="#"><i class="fa fa-shopping-cart"></i></a>
<a href="#">登录</a>
</div> -->
</div>
</header>
</body>
</html>
logo的a标签和下面的ul是兄弟节点。你选择器应该用class或者id标识,而不是选择所有的a。